BackgroundUndiagnosed obstructive sleep apnea (OSA) increases the risk of perioperative complications in bariatric patients. Validated screening methods exist, but are not specific to patients with severe obesity. ObjectivesDetermine the ideal OSA screening tool for bariatric surgery patients balancing accuracy and cost-effectiveness. SettingUniversity Hospital. MethodsBariatric surgery patients from January 2018 to September 2023 were identified from the Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program (MBSAQIP) database. For patients with a STOP-Bang score of ≥4 referred for polysomnogram additional variables were collected from the electronic medical record. The Berlin Score was retrospectively calculated. ResultsOut of 484 patients who underwent bariatric surgery, 167 (34.5%) had a STOP-Bang score ≥4. The receiver operating characteristic (ROC) curve for STOP-Bang scores ≥4 had an area under the curve (AUC) of 78.5% for predicting OSA and 83.7% for OSA requiring treatment (Apnea Hypopnea Index [AHI] ≥ 15), compared to Berlin Scores’ AUC of 80.7% and 88.6%, respectively. A STOP-Bang score of 4 had a sensitivity of 55.6% and specificity of 36.8%, while a score of 5 had 29.3% and 66.2%, respectively. A Berlin Score of 3 had a sensitivity of 47.5% and specificity of 69.1%, with 30 patients (44.1%) starting OSA treatment. Thirty-five patients (21%) experienced a delay in insurance submission, averaging 41.5 days, related to OSA workup. ConclusionThe Berlin questionnaire outperforms STOP-Bang in predicting OSA requiring treatment. Raising the polysomnography referral score from STOP-Bang ≥4 to ≥5 or utilizing a Berlin Score of ≥3, may alleviate resource burden, reduce costs, and expedite medical optimization for bariatric surgery.